We report on the study of extremely high energy photons, pions and etas, produced in intermediate energy heavy-ion collisions. Possibility of imaging the final-state phase space in these collisions by the BoseEinstein correlations for photons is critically examined. Invited talk given at the NATO Advanced Research Workshop on the Structure of Mesons, Baryons and Nuclei, Krakow (Poland), May 26 ...

pet (positron emission tomography) is a powerful imaging technique that can provide quantitative information on the distribution of positron emitter labeled radiopharmaceuticals (pet radiopharmaceuticals) in the body. positrons (ß+) are positively charged beta particles. they are emitted when the atom is proton rich. a positron has only a transient existence. after losing all of its kinetic ene...

The LHAASO Collaboration has reported their observation of very high energy photons (${E}_{\ensuremath{\gamma}}^{\mathrm{max}}\ensuremath{\simeq}18\text{ }\text{ }\mathrm{TeV}$) from the gamma-ray burst GRB221009A. sterile neutrino that involves both mixing and a transition magnetic moment may be viable explanation for these photon events. However, we demonstrate such solution is strongly disfa...

The total cross section for scattering virtual photons at high energy is sensitive to pomeron physics. If the photons are sufficiently virtual, QCD perturbation theory applies, so that the reaction probes the short distance pomeron. We study this reaction for present and future e*ecolliders. Submitted to Physical Review Letters. *Work supported in part by the Department of Energy, contracts DE-...

introduction the potential hazards posed by exposure to radiation from radon have been of great concern worldwide, since it is especially associated with increased risk of lung cancer. some radioisotopes of radon progeny deposited in the human lungs emit β particles followed by the γ rays. while γ rays are comparatively less damaging to the respiratory system than α and β particles, it is the p...